The indicators of measuring gauges with mechanical drives are fundamentally inexact because of the presence of parasitic frictional forces and the play in sprocket gears. Besides that, an up-to-date technical further improvement of the measurements through the use of mechanical measuring gauges is problematical and not possible.
Because of these reasons, new or already at-hand hardness testers have lately been outfitted (retrofitted) at great cost with electronic measurement systems. This requires not only a great production but also assembly expense in order to outfit an already existing apparatus with an electronic measurement system.
There is however, the need to modernize, make usable and to provide a suitable electronic measuring gauge which may be retrofitted for the large number of hardness testers, already in service for years, without such a large production an assembly expense.